FIG. 1 shows a conventional containable door of such a type, which is disclosed in an Unexamined Japanese Utility Model Application No. 62-75183. More specifically, a cabinet for a projection television set includes a pair of containable, folding doors (only one of which is shown) which can open away from each other. The pair of doors includes respective bodies 2 for covering the screen of the television set. The door body 2 comprises a pair of door panels 4 and 5 connected together by a hinge 3 so that the door body 2 can be folded. The door panel 4 is disposed adjacent to a side wall 1 of the cabinet whereas the door panel 5 is disposed adjacent to one end of the door panel 4 remote from the side wall 1. The other end of the door panel 4 is angularly movably connected to a slide member 8 through first and second metal hinge elements 6 and 7. A metal slide element 9 fixedly secured to the slide member 8 is engaged with a rail 10 for sliding movement therealong. The rail 10 is fixedly mounted on the side wall 1 and extending rearwardly from a position adjacent to the front of the cabinet. The first and second hinge elements 6 and 7 are pivotally connected together by a pivot pin 11, and a lock member 12 is also pivotally mounted on the pivot pin 11 and is interposed between the first and second hinge elements 6 and 7. The lock member 12 is urged in a clockwise direction (FIG. 1) by a torsion spring 13 acting between a projection 12a of the lock member 12 and the second hinge element 7.
In the closed condition (solid line in FIG. 1) of the door, the lock member 12 is engaged with a stopper or projection 14, formed on the side wall 1, to thereby prevent the slide member 8 from moving rearward or backward. When the door is folded to be opened as shown in phantom in FIG. 1, an upwardly-directed projection 6a formed on the first hinge element 6 is brought into engagement with a shoulder or stepped portion 12b of the lock member 12 to urge the lock member 12 to angularly move in a counterclockwise direction. As a result, the lock member 12 is disengaged from the stopper 14, so that the slide member 8 and the folded door body 2 connected to the slide member 8 can be slidably moved in a direction of an arrow A (FIG. 1) so as to be contained in the cabinet.
In this conventional containable door having a lock mechanism, the projection 6a, formed on the first hinge 6 connected to the door body 2, is adapted to be engaged with the stepped portion 12b of the lock member 12 to release the locking condition. In other words, such lock release depends on the angle of opening of the door (more specifically, the angle of opening of the door panel 4). Therefore, the timing of the lock release is not clear, and there is a risk that the locking is released even when the door body 2 is not fully folded, so that the slide member 8 and the door body 2 can move into the cabinet. Thus, the timing of the lock release cannot be controlled.